1. Field of the Invention
The present invention relates to an inertial instrument and more specifically pertains to single axis and multi-axis vibrating accelerometers used as multi-sensors for measuring linear acceleration and rate of rotation of a moving body.
2. Description of Prior Art
Gyroscopes and accelerometers are well known for use in sensing angular velocity and acceleration for determining location, direction, position and velocity of a moving vehicle.
A desire for miniaturization, reduced cost, and improved performance requires almost impossible accuracies in the actual structure of the accelerometer.
Two counter vibrating tuned accelerometers are formed in a single substantially planar silicon body to form the sense layer of the accelerometer gyro. The two accelerometers each having a dither mass (driven element) and proof mass (pendulum) are structurally interleaved in a manner that places the center of mass of the two accelerometers on a line parallel to the direction of vibration, and places the centers of percussion of the two proof masses at the same spot. Each accelerometer is subjected to a phase insensitive quadrature nulling method. A top and bottom cover for the sense layer is made of Pyrex, and uses metalized electrodes, contact pads, and vias to access and contain the sense layer. A container encapsulates the accelerometer package in a hermetically sealed environment. Access to the accelerometer is provided by feedthrus in the container walls